Celebrating the equinox at the pyramids of Teotihuacan in Mexico

Hundreds of people are seen taking part on the Spring Equinox at the Teotihuacan archeological zone in Teotihuacan, Mexico, on 21 March 2011. According to some beliefs, on this day the ancestral spirits and the cosmic forces are invoked to purificate the body and the soul. EPA/Alex Cruz

Ronaldo Schemidt / AFP - Getty Images

A hot air balloon flies over the Sun Pyramid at the Teotihuacan archaelogical site during the Teotihuacan Hot Air Balloon Festival in San Juan de Teotihuacan, State of Mexico, on March 21, 2011. The festival is being held on the spring equinox.